Hybrid circuit module having bridge circuit and rectifying circuit disposed on a same substrate

ABSTRACT

An electric circuit for supplying electrical power having a controlled frequency to a load includes thyristors, each having an anode terminal, a cathode terminal, and a gate terminal for supplying an electric current from the anode terminal to the cathode terminal; transistors, each having a collector terminal, an emitter terminal and a base terminal for switching ON/OFF an electric current from the collector terminal to the emitter terminal; an arm device connected between the cathode terminal of the thyristor and the collector of the transistor; bridge circuit device, having a plurality of arms between one terminal and another terminal of an electrical power source, so that the positive terminal is coupled to the anode terminal of the thyristors and the negative terminal is coupled to the emitter terminal of the transistor, and controlling circuit, connected to the load, for supplying an electric signal to the base terminal of the transistor to apply an electric voltage intermittently to the load, and supplying an electric signal to the gate terminal of the thyristors to supply an electric current periodically in accordance with the desired frequency between the anode and cathode terminals of the thyristor.

BACKGROUND OF THE INVENTION

The present invention relates in general to a hybrid electrical circuitand, more particularly, to a hybrid electric circuit device forsupplying electric power of a desirably controlled frequency to a loadsuch as an electric motor, which is applicable, for example, to afrequency conversion circuit.

The present invention also relates to a frequency conversion circuit,and is particular concerned with an output circuit thereof.

Generally, a prior art frequency conversion circuit is known asdisclosed in Japanese Patent Publication No. 62-42472, published Sept.8, 1987. The circuit described in the aforementioned publicationincludes circuit switching elements for changing the direction in whicha pulsating current is carried, each constituting thyristor elements,whereby a desired frequency is obtained from controlled an ignitiontiming of the thyristors.

Such prior art comprises a single thyristor module containing aplurality of thyristors for directly controlling power principally, asingle diode module containing a plurality of diodes for rectification,a drive circuit for the thyristors, and an ignition timing controlcircuit of the thyristors.

Since an ON/OFF characteristic of the thyristor is utilized, the priorart has a characteristic that the circuit automatically becomes off atthe zero cross time of an impressed pulsating current. Accordingly, thedirection of an electrical current to the load is changed generally atthe zero cross point, a frequency of the alternating current generatedfrom the frequency conversion circuit becomes one of the integral numberof a frequency of the utilized AC power, and thus a continuity at thetime of frequency variation is not satisfactory, an abnormal vibrationarises on a load, or the load gets locked otherwise.

Meanwhile, in the case where the frequency conversion circuit isconstituted of transistor elements, an arbitrary frequency can begenerated, however, an ON/OFF control circuit and an independent powersource for control will be necessary at every transistor element, andthus the circuit becomes inevitably large in size and complicated at thesame time, and the thyristor module and the diode module are connectedby a lead wire or wiring pattern. Accordingly, a pulsating current oflarge power flows to the lead wire or wiring pattern, and an significantelectromagnetic noise is radiated from the lead wire or wiring pattern,thus causing a noise interruption in a TV, audio equipment and othersuch devices. Then, since the thyristor module and the diode module areseparated from each other, the circuit size becomes large inevitably insize, and a troublefree a low operation is therefore not realized forthe circuit.

SUMMARY OF THE INVENTION

In view of such problems, an object of the present invention is toprovide a frequency conversion circuit having a simple configuration andcapable of providing an arbitrary frequency, and to further provide afrequency conversion circuit which achieves realizing miniaturizing andenhancement of reliability using a circuit comprising thyristors,transistors and rectifier diodes.

Another object of the invention is to provide a hybrid electricalcircuit device having a printed circuit base molded integrally withplastic material.

The present invention provides an electric circuit for supplyingcontrolled frequency electric power to a load comprising : thyristors,each having a gate terminal for supplying an electric current from itsanode terminal to its cathode terminal; transistor, each having a gateterminal for switching ON/OFF an electric current from its collectorterminal to its emitter terminal; series circuit means connected betweenthe cathode terminal of the thyristor and the collector terminal of thetransistor; a bridge circuit having a plurality of arms betweenterminals of an electric power source so that one terminal and the otherterminal are coupled to the anode terminal of the thyristor and theemitter of the transistor, respectively. A controlling circuit device isprovided to supply an electric signal to the the gate terminal of thethyristors and supplying an electric signal to the base terminal of thetransistor to supply an electric current periodically to the load inaccordance with the desired frequency. The transistor repeatedlyprovides an ON/OFF state while the thyristor is in an ON state.

The present invention provides also an electric circuit for supplying asingle-phase electrical power which permits miniaturization andenhancement of the reliability by thyristors, transistors and rectifierdiodes.

Also, the present invention provides a hybrid circuit device forsupplying electric power to a load comprising: printed circuit basemeans, molded integrally with plastic resin, for supplying electricpower to the output terminals; a plurality of switching semiconductorsforming a bridge circuit and adapted to provide ON/OFF switchingoperation to supply electric power of a desired frequency; and aplurality of rectifier diodes for rectifying the AC power and thenfeeding the rectified power to the switching semiconductors. The bridgecircuit can have arms each of which has a thyristor and a transistorconnected in series to the thyristor. Alternatively, the bridge circuitcan be formed with arms each having two transistors that are connectedtogether in series. In an embodiment, the sensor is provided to sensetemperature of the switching semiconductors.

In the molded structure described above, a radiation of electromagneticnoise will be prevented by shortening a lead wire or wiring patternthrough which a large current flows, and the circuit can also beminiaturized as a whole.

In the single-phase frequency conversion circuit constructed as above, aradiation of electromagnetic noise will be prevented by shortening alead wire or wiring pattern through which a large power flows, and thecircuit can also be miniaturized as a whole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frequency conversion circuit diagram embodying the presentinvention,

FIG. 2 is a diagram illustrating the case where a 60 Hz output isobtained using the circuit shown in FIG. 1,

FIG. 3 is a diagram illustrating a zero cross output,

FIG. 4 is an enlarged diagram showing an output waveform in one cycle,

FIG. 5 is a diagram showing the ON/OFF state of a photocoupler at eachoperation mode,

FIGS. 6 and 7 are operational flowcharts of the main operation of thecontrolling part shown in FIG. 11,

FIG. 8 is a diagram showing constant data of the output frequency,

FIG. 9 is a diagram illustrating the case where another frequency outputis obtained,

FIG. 10 is an electric circuit diagram representing the circuit shown inFIG. 1 by means of the molded device shown in FIG. 11 or 13,

FIG. 11 is a hybrid circuit diagram of a molded device to a conversioncircuit according to the present invention,

FIG. 12 is a sectional view taken along XII--XII in FIG. 11 showing themolded device, and

FIG. 13 is a frequency conversion circuit diagram according to anotherembodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will be described with reference to theaccompanying drawings representing preferred embodiments thereof. Theillustrated embodiments merely shows preferred embodiments of theinvention and directed to a single-phase conversion circuit for thepurpose of clarification only, but the present invention is not limitedto the description of the preferred embodiments.

Referring first to FIG. 1 showing an electronic circuit of a main partof a single-phase conversion circuit, a thyristor 1 has a cathodeterminal connected to a collector terminal of a transistor 2. Anignition circuit having a photocoupler 3 is provided on a gate terminalof the thyristor 1. The thyristor 1 and the photocoupler 3 are connectedto self-bias resistors 4 and 5, respectively. A bias circuit having adriving transistor 6 and a photocoupler 7 is provided on a base terminalof the transistor 2. The transistors 2 and 6 are connected at their baseterminals with base resistors 9 and 8, respectively. A thyristor 10,similar to the thyristor 1, has an ignition circuit having aphotocoupler 11 on a gate terminal of the thyristor 10. The thyristor 10and the photocoupler 11 are connected with self-bias resistors 13 and12, respectively. A transistor 14, similar to the transistor 2, isconnected at its base terminal with a bias circuit having a drivingtransistor 15 and a photocoupler 16. The transistors 14 and 15 areconnected at their base terminals with base resistors 18 and 17,respectively. The thyristors 1, 10 and the transistors 2, 14 aremaintained in an ON state when the photocouplers are in an ON state.

A single-phase load 19 or, for example, a single-phase electric motorand the like, has one end connected to a connection point between thecathode terminal of the thyristor 1 and the collector terminal of thetransistor 2, and the other end connected to a connection point betweena cathode terminal of the thyristor 10 and a collector terminal of thetransistor 14.

A constant voltage circuit 20 is provided to generate +Vcc voltage,which is supplied to the transistors 6, 15 and the photocouplers 7, 16.The constant voltage circuit 20 has a rectifying part, a smoothing partand a stabilizing part, not shown.

A rectifying circuit 21 has four rectifying diodes 202, 203, 204, 205connected in the form of a full bridge. A pulsating voltage rectified bythe rectifying circuit 21 is impressed between anode terminals of thethyristors 1, 10 and emitter terminals of the transistors 2, 14.

A two-way photocoupler 22 is connected between the output terminals of autilized AC power source 201. An output of the photocoupler 22 is asillustrated by the item "(b)" when the operating voltage of a lightemitting diode(LED) 206, 207 used on a phototransistor is taken intoconsideration, whereas the item (a) represents an output waveform of theutilized AC source. An output for which the output waveform is invertedby an inverter 23, that is, waveform shown in the item "(c)", is fed toa controlling part 24 (i.e., microcomputer or the like). The outputcorresponds to a zero cross output of the utilized AC power source.

The controlling part 24 controls a frequency of the power fed to theload 19 according to a frequency signal incoming from a terminal F,lighting up the photo thyristors 209, 210, photo transistors 211, 212,and photo thyristors 213, 214 of the photocouplers 3, 7, 11 and 16through a buffer 25 to determine an output frequency. Reference numerals217-220 denot reverse-blocking diodes, and reference numerals 221 and222 denote capacitors.

In FIG. 2 of the drawings, (a) shows the pulsating current output of therectifying circuit 21, (b) shows the zero cross output of the AC powersource, (c) shows the outputs of the photocouplers (A)3, (B)7, (C)11,(D)16 for obtaining the 60 Hz output, and (d) shows the voltageimpressed on the load 19. The arrow shown in full line and that shown indotted line in (d) depict the directions of the voltage impressed so asto carry an electric current in the directions indicated by the arrowshown in full line and that shown in dotted line of the load 19 shown inFIG. 1, respectively. That is, an electric current flows in thedirections indicated by arrows in FIG. 1 when a voltage is impressed inthe directions indicated by arrows in FIG. 2. Accordingly, whenobtaining the 60 Hz output, the direction in which an electric currentis carried may be changed according to the zero cross output shown in(d). In this case, a voltage which is the same as a rated voltage of theAC power source is impressed on the load.

In FIG. 2, (e) and (f) show the changing of a mean voltage impressed at60 Hz in an output frequency, wherein impression of the voltage isinterrupted T Time after (t₁) a zero crossing time (t₀), and furtherimpression of the voltage is recommenced T time thereafter (t₂). Forimpressing such a voltage waveform, an ON/OFF operation of thephotocopier (B) (transistor 2) will be controlled to the times t₀, t₁,t₂, t₃ with the photocoupler (C) (thyristor 11), for example, kept on.The period of time T₁ +T₂ +T₃ covers a half cycle of 60 Hz, and T₁ =T₂in this case. Accordingly, the time between T₁ and T₂ may be set oncharacteristics such as efficiency, output and the like of the load 19.

Accordingly, the controlling part 24 comprises controlling ON states ofthe photocouplers (A)3, (B)7, (C)11, (D)16 so as to obtain outputwaveforms shown in FIG. 2 (see also FIG. 1).

In the conversion circuit constructed as above, the full-wave rectifyingcircuit 21, the thyristors 1, 10 and the transistors 2, 14 are containedwithin the device 27, and the length of the wiring pattern forconnecting the rectifying circuit 21 and the thyristors 1, 10 or thetransistors 2, 14 can be made shorter. Accordingly, an effective lengththat the wiring pattern functions as an antenna becomes short, thusdecreasing the radiation of electromagnetic noise. Further, a use of thedevice may realize a compaction of the circuit and thus aminiaturization of the conversion circuit.

In the above-described embodiment of the invention, by molding therectifier element and the plurality of switching elements integrally, aneffective length in which the wiring or wiring pattern for connectingthe rectifier element and the switching elements functions as an antennacan be shortened, a radiation of electromagnetic noise due to a carriedpulsating current will be suppressed, and thus an influence to beexerted on other electronic equipment can be suppressed. Further, byusing such a device, the space utilized can be lessened, and theelectric circuit can be miniaturized as a consequence.

An example of the conversion according to the invention will bedescribed specifically. The following description is subject to thefrequency of a utilized AC power source being set into five stages at 60Hz, 40 Hz, 30 Hz, 24 Hz and 20 Hz.

FIGS. 6 and 7 are operational flowcharts for obtaining theaforementioned outputs, namely operational flowcharts of the controllingpart 24 shown in FIG. 11. FIG. 8 represents data at each frequency,wherein a mean voltage impressed on the load is determined according totimes T₀, T₁, a reference character "m" represents a count number ofzero cross output indicating an end of one period, and "n" represents acount number of the mode in a half period. That is, the direction inwhich an electric current is carried to a load is transferred from thedirection indicated by the arrow shown in full line to that of arrowshown in dotted line when "n" reaches a predetermined count number, andthe current carrying direction is transferred from the directionindicated by the arrow shown in dotted line to that of the arrow shownin full line when "m" reaches a predetermined count number. Thus, theend of one period is detected on the count number of zero count output,therefore the frequency can be changed in accordance with the zero crossoutput at all times. First, starting and constant setting are carriedout at steps s₁ (F=1, M=0, N=0). A frequency signal applied to theterminal F is supplied at step S₂, and data (m, n, T₀, T₁) according tothe frequency is read from the table of FIG. 8. Next, a presence of thezero cross output is detected at step S₃ so that a first mode output inthe half cycle can be synchronized with the zero cross output at alltimes. When the zero cross output is present, "1" is added to M and N toshift the next mode, and a new half cycle starting is set at step S₄.Next, whether "N≧n" is determined at step S₅. That is, whether theoutput waveform is on the side of the arrow shown in full line (positiveoutput) or on the side of the arrow shown in dotted line (negativeoutput) is decided, and when "N≧n", the flag is rewritten to F=0(indicating negative output) at step S₆. Accordingly, I mode output(positive output) or III mode (negative output) is decided to a value ofthe flag and then so generated. The output is maintained for the time T₁thereafter at step S₇. Whenever the time is up, "1" is added as N=N+1 atstep S₈ to the next mode output. Whether the next mode is II mode(positive output) or IV mode (negative output) is determined at step S₉and so generated. The output is kept maintained for the time T₀thereafter at step S₁₀. After the time is up, "1" is added as N=N+1 atstep S₁₁ to the next mode output. Whether or not "N≧n", that is, whetheror not the output is changed to a negative output is determined at stepS₁₂ in this case, and if "N≧n", then "F=0". Whether I mode output(positive output) or III mode (negative output) is decided thereafter atstep S₁₃ and so generated. Next, "M≧m", that is, whether or not theoutput for one period ends at the last mode of half cycle is decided atstep S₁₄, and when the output for one period is finished, F,M and N aredetermined as F=1, M=0, and N=0 at step S₁₅ to return to step S₂, andwhen not yet finished, the mode output decided at S₁₃ is kept until thetime is up on the zero cross output at S₃.

In the above-described embodiment, whether the output is positive ornegative is decided at the first and last modes of half cycle, andwhether or not the output for one period ends is decided at each lastmode of the half cycle, however, the case where the output frequency isset to other frequency than the above-mentioned embodiment is notnecessarily limited thereto.

FIG. 9 is a diagram showing a state when a 40 Hz output is obtained,wherein the 40 Hz output frequency (60/1.5=40 Hz) is obtainable fromcarrying the latter half pulsating current second from the left in thedirection indicated by an arrow in dotted line, that is, making a halfcycle of the output waveform 1.5 times. ON states of the photocouplers(A), (B), (C), (D) in this case may be controlled as shown by the item(j) in FIG. 9. As in the case of item (i) in FIG. 2, a non-currentcarrying time T₀ will be provided and a mean voltage impressed on theload may be regulated to an efficiency of the load. Items (k), (l), (m),(n) in FIG. 9 indicate output waveforms when outputs of 40 Hz, 30 Hz, 24Hz, 20 Hz are obtained, respectively.

To obtain various frequency outputs shown in FIG. 9, a combination ofwaveforms in one cycle of the utilized AC power source may be changed.FIG. 4 is an enlarged view of the one cycle (see item (i) in FIG. 1),wherein if a current carrying time to the load is T₁ and a non-currentcarrying time is T₀ (the aforementioned time), then the one cycle can bedivided into T₁ →T₀ →T₁ →T₁ →T₀ →T₁, and a combination of ON states ofthe photocoupler at each time can be classified into I mode→II mode→IIImode→IV mode→III mode (for each mode status refer to FIG. 5). Theillustration is that for obtaining 60 Hz output, however, when comparedwith other frequency outputs shown in FIG. 9, the time is repeated allthe time as T₁ →T₀ →T₁ notwithstanding that the output frequency varies.Accordingly, different frequency outputs will be obtainable by changingan output order of I mode to IV mode. For example, when obtaining 40 Hzoutput, the mode comes in I→II→I→I→II→III→III→IV.fwdarw.III (for oneperiod), while the time is as T₁ →T₀ →T₁ →T₁ →T₀ →T₁ →T₁ →T₀ →T₁ (forone period).

In the invention, since arms with a cathode terminal of the thyristorconnected to a collector terminal of the transistor are connected inparallel into two circuits, and a single-phase load is connected betweennodes of the cathode terminal and the collector terminal of each arm, acarried current controlled by the thyristor is chopped by the transistorand an output of the half cycle can be divided at every plural time.Accordingly, an operation similar to the case where the circuit isconfigured entirely by transistors is obtainable even from usingthyristors, and thus the cost can be significantly reduced from usingthe thyristors, an independent power source for ignition circuit becomesunnecessary as compared with the transistors, thus simplifying thecircuit.

FIG. 10 shows an electronic circuit which has some change in layout fromthat of FIG. 2. In FIG. 10, the thyristors 1, 10, the transistors 2, 14,the full-wave rectifying circuit 21 and a temperature senser 28 whichare shown in FIG. 11 are molded and separated within a single module 27.A temperature protecting part 26 outputs a signal to the controllingpart 24 to a current carrying to the load when the temperature detectedby the temperature senser 28 connected through terminals 3, 3' reaches apredetermined temperature.

FIG. 11 is an internal circuit diagram of the molded device 27 connectedto terminals 1 through 12 shown in FIG. 10. The thyristors 1 and 10 canbe replaced by transistors 1', 10' as illustrated in FIG. 13. In FIGS.11 and 13, reference numerals 101-104 represent rectifying diodes,numerals 105-108 represent reverse-blocking diodes, and numerals 109 and110 represent transistors.

FIG. 12 is a longitudinal sectional view of the molded device 27 shownin FIG. 11. In FIG. 12, the device 27 has an insulation layer 30 on analuminum substrate 29, a wiring pattern 31 on the insulation layer 30, achip 32 of the transistor, a lead wire 33 extending outwardly forconnection with external electrical elements, an outer frame 34 of asuitable synthetic resin, a terminal 301 and a filler 35 of a suitablesynthetic resin filled in a space between the outer frame 34 and thealuminum substrate 29.

While the invention has been described in the specification andillustrated in the drawings with reference to preferred embodiments ofthe single-phase frequency conversion circuit device, it will beunderstood by those skilled in the art that various changes may be madeand equivalents may be substituted for elements thereof in accordancewith applications and technical field to be applied without departingfrom the scope of the invention. In addition, many modifications may bemade to adapt a particular situation or material to the teachings of theinvention without departing from the essential scope thereof. Therefore,it is intended that the invention will not be limited to the particularembodiment illustrated by drawings contemplated for carrying out thepresent embodiments falling within the description of the appendedclaims.

What is claimed is:
 1. A hybrid circuit module molded by electricallyinsulating and thermally conductive material for supplying controlledfrequency electric power to a load comprising:a substrate plate ofthermally conductive material having output terminals for supplyingelectric power to said load; input terminals for supplying A.C. power;signal terminals for receiving ON/OFF switching signals; and electricalconductors connecting said output terminals, input terminals and signalterminals to form a hybrid circuit, wherein said hybrid circuitincludes: a converting circuit means comprising a plurality ofrectifying diodes electrically connected together for rectifying saidA.C. power received via said input terminals; a bridge circuit means,located adjacent to said converting circuit to thus shorten a length ofelectrical conductors between said converting circuit and said bridgecircuit, said bridge circuit means comprising a plurality ofsemiconductor switching elements connected in a bridge form forswitching ON/OFF in response to said switching signals received via saidsignal terminals, wherein, when switching signals are supplied to saidsignal terminals by a predetermined ON/OFF combination, a rectifiedoutput from said converting circuit is transformed into an electricpower of a predetermined controlled frequency and said electric power issupplied from said output terminals to said load.
 2. The hybrid circuitmodule according to claim 1, further comprising temperature sensingmeans adjacent to said bridge circuit, said temperature sensing meansbeing molded with the electrically insulating and thermally conductivematerial together with said bridge circuit, said temperature sensingmeans for controlling said semiconductor switching elements to switchOFF when a detected temperature is above a predetermined temperature. 3.The hybrid circuit module according to claim 1, wherein saidsemiconductor switching elements are transistors.
 4. The hybrid circuitmodule according to claim 1, wherein said bridge circuit furthercomprises a plurality of arms, each of said arms having a thyristor anda transistor connected in series to said thyristor so that an electriccurrent flows in a same direction.
 5. A hybrid circuit module molded byelectrically insulating and thermally conductive material for supplyingcontrolled frequency electric power to a load comprising:a substrateplate of thermally conductive material having a hybrid circuit, whereinsaid hybrid circuit comprises: a converting circuit means comprising aplurality of rectifying diodes electrically connected together forrectifying an A.C. power; and a bridge circuit means, located adjacentto said converting circuit to thus shorten a length of electricalconductors between said converting circuit and said bridge circuit, saidbridge circuit comprising a plurality of arms, each of said arms havinga thyristor and a transistor connected in series to said thyristor sothat an electric current flows in a same direction, wherein, whenswitching signals are supplied to said thyristor and said transistor bya predetermined ON/OFF combination, a rectified output from saidconverting circuit is transformed into an electric power of apredetermined controlled frequency and said electric power is suppliedto said load.